Revision of gonadal radiation dose to man from thallium-201
Thallium-201 as thallous chloride is now routinely used for myocardial imaging. We observed a biological translocation of T1-201 leading to a gradual increase in the concentration of radioactivity in the testes which facilitated testicular imaging. The initial distribution of intravenously injected tracer dose is greatly dependent on the distribution of cardiac output, but its metabolic fate is analogous to the potassium ion. We have extensively studied the kinetics of thallium in rats, and also carried out limited comparative studies in different species. An attempt was also made to compare the uptake values that could be obtained in dogs by quantitative imaging and by autopsy. Separation of scrotum, epididymis and testes revealed that the increase in uptake occurred predominantly in the testes. The uptake increased with time for about 1 day, and after 2 days it declined with a biological half-life of approximately 2 days. The later phase of testicular clearance was similar to the rate of clearance from other organs. The testicular uptake of T1-201 was highest in rats: the initial value at 10 to 15 min was 0.48 +- 0.09% of the injected dose which increased to 1.77 +- 0.20% by 1 day. The initial uptake in mice was low (0.18 +- 0.06%) but it increased to about 4 folds by 1 day. Values in human, extrapolated from limited quantitative imaging, was similar to mice. These studies indicated the need for the revision of the gonadal radiation dose to man. Calculations show, contrary to the accepted value of about 0.5 rads/mCi, an approximate value of 1.5 rads/mCi is more realistic.
- Research Organization:
- Univ. of Texas, Houston
- OSTI ID:
- 5870050
- Report Number(s):
- CONF-801082-; TRN: 82-003970
- Journal Information:
- HHS Publ. (FDA) (U.S.); (United States), Vol. 81-8166; Conference: ORAU radiopharmaceutical dosimetry symposium, Oak Ridge, TN, USA, 6 Oct 1980
- Country of Publication:
- United States
- Language:
- English
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62 RADIOLOGY AND NUCLEAR MEDICINE
TESTES
BIOLOGICAL RADIATION EFFECTS
THALLIUM 201
BIOLOGICAL LOCALIZATION
DIAGNOSTIC USES
DOSIMETRY
EXTRAPOLATION
LABORATORY ANIMALS
MYOCARDIUM
PATIENTS
RADIATION DOSE DISTRIBUTIONS
RADIATION DOSES
RADIONUCLIDE KINETICS
SCINTISCANNING
SIDE EFFECTS
THALLIUM CHLORIDES
BETA DECAY RADIOISOTOPES
BIOLOGICAL EFFECTS
BODY
CARDIOVASCULAR SYSTEM
CHLORIDES
CHLORINE COMPOUNDS
COUNTING TECHNIQUES
DAYS LIVING RADIOISOTOPES
DIAGNOSTIC TECHNIQUES
DOSES
ELECTRON CAPTURE RADIOISOTOPES
GONADS
HALIDES
HALOGEN COMPOUNDS
HEART
HEAVY NUCLEI
ISOMERIC TRANSITION ISOTOPES
ISOTOPES
MALE GENITALS
MUSCLES
NUCLEI
NUMERICAL SOLUTION
ODD-EVEN NUCLEI
ORGANS
RADIATION EFFECTS
RADIOISOTOPE SCANNING
RADIOISOTOPES
SECONDS LIVING RADIOISOTOPES
THALLIUM COMPOUNDS
THALLIUM ISOTOPES
USES
560171* - Radiation Effects- Nuclide Kinetics & Toxicology- Man- (-1987)
560172 - Radiation Effects- Nuclide Kinetics & Toxicology- Animals- (-1987)
560161 - Radionuclide Effects
Kinetics
& Toxicology- Man
550601 - Medicine- Unsealed Radionuclides in Diagnostics